Plasma-wave generation in a dynamic spacetime

We propose a new electromagnetic-emission mechanism in magnetized, force-free plasma, which is driven by the evolution of the underlying dynamic spacetime. In particular, the emission power and angular distribution of the emitted fast-magnetosonic and Alfv\'en waves are separately determined. Previous numerical simulations of binary black hole mergers occurring within magnetized plasma have recorded copious amounts of electromagnetic radiation that, in addition to collimated jets, include an unexplained, isotropic component which becomes dominant close to merger. This raises the possibility of multimessenger gravitational-wave and electromagnetic observations on binary black hole systems. The mechanism proposed here provides a candidate analytical characterization of the numerical results, and when combined with previously understood mechanisms such as the Blandford-Znajek process and kinetic-motion-driven radiation, allows us to construct a classification of different electromagnetic radiation components seen in the inspiral stage of compact-binary coalescences.Comment: 7 pages, 1 figure, published versio